US 5,281,190 A · Gear thrust controlled multi-mode clutch for power transmissions

Abstract

Multi-mode friction clutch having a plurality of interleaved clutch plates operable for establishing gear ratios in planetary and countershaft type automatic transmissions and operative to provide smooth and self-synchronized shifting without the use of one-way roller or sprag clutches. Gear thrust forces from associated helical gearing and opposing hydraulic pressure forces are used to regulate the hydraulic pressure of a piston chamber by shifting an annular control sleeve which controls fluid exhaust from the chamber to maintain a direct relationship between the torque capacity of the clutch and the variable torque it actually carries. Consequently, the clutch is automatically released when the transmitted torque diminishes to zero or reverses. The clutch is applied in a normal lock mode for predetermined gear ratios, set in one-way mode for shifting and totally released when the shift is completed. The multi-mode clutch is applicable to a chain driven multi-axis countershaft transmission construction, which further foreshortens the transmission for improved utilization of the space allocated for vehicle powertrains.

Claims19

Dependent claims

A multi-mode friction drive establishing device for a transmission having torque input and output means and gear means operable to provide a plurality of forward drive gear ratios and a reverse ratio comprising,

a housing,
first friction means operatively connected to said housing,
a support,
second friction means operatively mounted on said support and associated with said first friction means and engagable therewith to define a friction device to transmit torque,
piston means operatively mounted in said housing to define a chamber therein for receiving pressurized fluid and being operative to effect frictional engagement of said first and second friction means so as to transmit torque,
gear set means operatively connected with said support having helical gear means which produces a variable thrust force from the torque transmitting device,
fluid pressure control means for selectively supplying pressure fluid to said chamber to effect the frictional engagement of said first and second friction means by said piston means for the drive of said gear set means,
exhaust means being selectively conditionable for exhausting fluid pressure from said chamber for effecting the frictional release of said first and second friction means,
control means associated with said exhaust means and movable in response to opposing gear thrust and fluid pressure forces exerted thereon by said helical gear means and said pressure fluid in said chamber to effect the regulation of fluid pressure in said chamber which decreases as the torque transmitted by said gear set means decreases and increases as the torque transmitted by said gear set means increases.

6 more elements

In combination with a countershaft transmission having drive torque input means for selectively driving any of a plurality of stepped drive gear ratios and having torque output means driven by any of said stepped drive gear ratios, separate multi-mode clutch means associated with each of said stepped drive gear ratios selectively operable for establishing separate power paths through said drive gear ratios to said transmission output means, each of said multi-mode clutch means having a rotatable housing and clutch housing drive means operatively connected to said drive torque input means so that said clutch housings can be driven thereby, each of said clutch housings having first friction plate means operatively connected to said associated housing and second friction plate means associated with said first friction means, a separate support means for supporting said second friction plate means of each of said multi-mode clutch means and forming the output thereof, each of said drive gear ratios being defined by a separate helical gear set associated with each of said multi-mode clutch means, each of said gear sets having an input helical gear adapted to be driven by the output of an associated one of said clutches when frictionally engaged and having an output helical gear for driving a torque transmitting shaft means adapted to be operatively connected to said output means of said transmission,

each of said housings having piston means operatively mounted therein to define a fluid pressure chamber for receiving pressurized fluid for the frictional engagement of said first and second friction plate means,
fluid pressure supply means for selectively supplying fluid pressure to said chamber to effect the frictional engagement of said first and second friction plate means by said piston means for the drive of said associated helical gear set means,
exhaust means associated with each of said chambers selectively conditionable for exhausting fluid pressure from said chamber, and
control means for said exhaust means and movable in response to the opposing forces of helical output gear thrust and the apply pressure in said chamber to regulate the fluid pressure in said chamber which decreases as the torque transmitted by said associated gear set decreases and increases as the torque transmitted by said associated gear set increases so that an automatic upshift transition between said stepped drive ratios occurs when said higher ratio establishing device has gained sufficient capacity to carry the input torque and the lower ratio establishing device experiences a reduction in torque capacity in accordance to the diminishing torque it carries until the clutch completely releases when such torque reduces to zero.

1 more element

In a transmission, input means for inputting torque into said transmission, a plurality of selectively engagable clutches, each of said clutches having a rotatable housing, drive means connected to said input means for driving each of said clutch housings, each of said clutches having an output, a torque transmitting shaft adapted to be driven by said gear set when said associated clutches are selectively engaged, each of said clutches having first friction plate means operatively connected to said rotatable housing, each of said outputs having second friction means associated with said first friction means, an output means for said transmission,

first gear set means including a first gear driven by said input means and an associated gear driven by said first gear for establishing a first gear ratio for said transmission,
second gear set means having a second gear driven by said output of one of said clutches and an associated gear adapted to be connected to said output shaft to establish a second ratio for said transmission,
third gear set means having a third gear driving by the output of said another of clutch means and an associated gear driven by the third gear and adapted to drive the output of said transmission,
fourth gear set means having a fourth gear adapted to be driven by the output of said yet another clutch means,
said fourth gear meshingly engaged with the associated gear of said third gear set means and being adapted to drive said third associated gear to establish the fourth forward gear ratio of said transmission.

2 more elements

In a transmission, input means for inputting torque into said transmission, a plurality of clutches, each of said clutches having a rotatable housing, drive means connected to said input means for rotatably driving each of said clutch housings, each of said clutches having an output drum and having first friction plate means operatively connected to said rotatable housing, each of said outputs drums having second friction means associated with said first friction plate means, an output means for said transmission,

first gear set means including a first gear driven by said input means and an associated gear driven by said first gear for establishing a first gear ratio for said transmission,
second gear set means having a second gear with helical teeth driven by said output of a second gear ratio drive clutch and an associated gear with helical teeth meshing with the helical teeth of said second gear and adapted to be connected to said output means of said transmission to establish a second gear ratio for said transmission,
said housing of at least one of said clutches having hydraulically actuated piston means operatively mounted therein defining a fluid pressure chamber therein, said piston means being adapted for movement between a first position in which said friction plates are frictionally separated so that they can relatively rotate without transferring appreciable drive torque and a second position in which said friction plates are frictionally engaged so as to transfer appreciable drive torque,
means for supplying said fluid chamber with a pressure fluid to effect the movement of said piston to an apply position,
means defining an exhaust port for exhausting fluid from said chamber to effect the release of said friction plates by said piston,
control sleeve means having a pressure surface within said chamber so that hydraulic pressure fed to said chamber can exert a force in a first direction to move said sleeve to effect the opening of said exhaust port so that said clutch is released for shifting said transmission,
said control sleeve having a second pressure surface for receiving the thrust load of said helical gears to urge said control sleeve in a direction opposite to said first direction to close said exhaust port to allow said pressure to building said chamber to effect the movement of said piston to said second position whereby said clutch is frictionally engaged for shifting said transmission.

4 more elements

Dependencies are inferred from the claim text.

Gear thrust controlled multi-mode clutch for power transmissions

Life of this patent

Gear thrust controlled multi-mode clutch for power transmissions

Life of this patent

Abstract

Claims19